Muncy climate

Muncy Frost Dates and Growing Season

NOAA 1991-2020 normals for Williamsport, 12.2 km from Muncy, elevation 520 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Williamsport. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around April 24 and the first fall freeze around October 23, a growing season of about 180 days.

Median at 36°F
last May 6, first October 10
Median at 32°F
last April 24, first October 23
Median at 28°F
last April 12, first November 3

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FMay 23May 18May 13May 9May 6May 2Apr 30Apr 26Apr 22
32°FMay 11May 6May 1Apr 28Apr 24Apr 22Apr 19Apr 16Apr 12
28°FApr 29Apr 21Apr 18Apr 15Apr 12Apr 8Apr 5Apr 2Mar 29
24°FApr 12Apr 7Apr 4Apr 1Mar 31Mar 28Mar 24Mar 20Mar 15
20°FApr 1Mar 29Mar 25Mar 23Mar 20Mar 17Mar 13Mar 9Mar 4
16°FMar 24Mar 19Mar 16Mar 13Mar 10Mar 7Mar 3Feb 27Feb 21

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 28Oct 2Oct 5Oct 7Oct 10Oct 13Oct 16Oct 20Oct 25
32°FOct 6Oct 11Oct 15Oct 19Oct 23Oct 27Oct 30Nov 2Nov 5
28°FOct 20Oct 26Oct 30Nov 1Nov 3Nov 6Nov 9Nov 12Nov 17
24°FNov 3Nov 6Nov 10Nov 13Nov 16Nov 18Nov 22Nov 26Dec 1
20°FNov 13Nov 17Nov 21Nov 25Nov 28Dec 1Dec 4Dec 8Dec 14
16°FNov 24Nov 29Dec 3Dec 6Dec 10Dec 15Dec 19Dec 23Dec 28

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F176169165160156152148144136
32°F199194188184180175171166158
28°F225218214210205202198193184
24°F250244240235232228224219213
20°F278269263258253250246240233
16°F300293287282277273268262254

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
5,774
Cooling degree days, base 65°F
796
Growing degree days, base 40°F
5,307
Growing degree days, base 45°F
4,122
Growing degree days, base 50°F
3,083
Growing degree days, base 55°F
2,182
Growing degree days, base 60°F
1,416

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,15601
February97701
March815018
April4456109
May18048340
June28160582
July2273736
August6222680
September9080441
October3829150
November693023
December1,00002

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 12.2 km from Muncy. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00014778 (Williamsport). Public domain.